This application relates to the field of optical coupling, and more particularly, to the field of diffractive grating in-coupling and out-coupling of guided optical waves.
Current communications systems are being stressed due to the ever increasing demand for greater bandwidth to handle evolving communications needs. More and more, telecommunications systems are evolving to meet these needs by employing optical signaling systems which employ optical fiber and specialized optical circuits and components.
The creation of such optical components has become a time consuming and expensive proposition. The optical fibers and optical circuits manufactured today are microscopic in size, where typical optical waveguides feature a cross-section of but a few microns in diameter.
Due to the size of optical waveguides and optical circuitry and other factors, current processes employed in their manufacture can be very costly and labor intensive.
With regard to particular components employed to couple a guided wave from one optical waveguide to a detector or another waveguide, or to couple a light source to a waveguide, this is especially the case. In these couplers, oftentimes a lens is employed to focus the exiting light so as to allow the light to enter a second waveguide without obstruction or loss. Positioning of such a lens is quite labor intensive, as are the subsequent steps of packaging the overall device, translating into a very high cost. This high cost impedes the overall creation of optical communications systems. Consequently, there is a need for a system and method for producing differactive couplers simply, thereby allowing such components to be manufactured at significantly reduced cost with low labor requirements.
The present invention solves the above-described problems by providing a phase mask for creating multiple diffraction gratings simultaneously. As described in U.S. patent application Ser. No. 09/165,822, a diffraction grating can be created to be used as an optical coupler. The present invention provides a phase mask incorporating multiple diffraction gratings for simultaneous production of multiple diffractive optical couplers. The present invention allows the optical couplers described in U.S. patent application Ser. No. 09/165,822 to be produced in large quantities while significantly reducing the cost and labor required.
The phase mask is produced by creating a plurality of diffraction gratings using the method disclosed in Ser. No. 09/165,822. The method disclosed in Ser. No. 09/165,822 teaches splitting a coherent light beam into a first coherent light beam and a second light beam. The first coherent light beam is directed into a first lens and onto an optical component, such as a prism. The second coherent light beam is directed into a second lens and onto the optical component. The optical component optically transmits the first and second coherent light beams into a recording material to create a grating.
Using that method, the phase mask can be designed to produce a plurality of volume gratings on a recording material. In one embodiment, the phase mask uses a pair of volume gratings to produce an interference pattern to create a third volume grating on the recording material. In another embodiment, the phase mask can incorporate multiple volume gratings to simultaneously create multiple third volume gratings on the recording material.
Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the claims.